Arrangement for cryogenic cooling

Abstract

An arrangement for cryogenic cooling includes a cryogen tank, a cryogenic recondensing refrigerator arranged to cool a heat exchanger that is exposed to the interior of the cryogen tank, and an arrangement for conducting heat from a cooled article to the cryogen tank. A further cryogen tank is provided below the heat exchanger and arranged to receive cryogen liquid recondensed on the heat exchanger.

Description

BACKGROUND OF THE INVENTIONField of the Invention[0001]The present invention relates to the cryogenic cooling of sensitive equipment, particularly in the context of superconducting magnets for MRI (Magnetic Resonance Imaging) systems.Description of the Prior Art[0002]As is well known to those skilled in the art, superconducting magnets comprise coils of superconductive wire which require cooling to cryogenic temperature appropriate to the material of the superconducting wire to maintain their superconducting properties. This is commonly achieved by at least partially immersing coils of superconducting wire in liquid cryogen at its boiling point.[0003]Different superconducting materials are known, and the cryogen must be chosen to have a boiling point below the superconducting transition temperature of the appropriate material. Liquid helium is often used. It has the lowest boiling point of all, about 4K, but is increasingly scarce and expensive.[0004]To reduce consumption of helium,...

AI Technical Summary

Benefits of technology

This arrangement provides efficient cooling of both magnet coils and electrical components, preventing quenches and maintaining stable superconducting conditions by ensuring continuous cryogen circulation and adequate cooling without reducing the cryogen capacity for the magnet coils.

Problems solved by technology

It has the lowest boiling point of all, about 4K, but is increasingly scarce and expensive.

However, such an arrangement has certain drawbacks.

In arrangements such as represented in FIG. 1, the components can suffer from insufficient cooling.

However, cooling of the components through mechanical contact has been found to be inefficient in a vacuum, as compared to cooling in contact with a cryogen liquid or gas as there is no cryogen to bridge any small contact gaps.

While this ensures effective cooling, this arrangement does have some drawbacks.

This may allow the components to heat above their superconducting transition temperature, which in turn could cause the magnet to quench.

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